[#168090759], [#157793674] Minor bug fix
[#168090759], [#157793674] Minor bug fix

* As a result of the changes for the two above stories, closing a case
table was broken. Handle the case where CaseTableView.visibleFrameBounds
is called, but no longer in the page.

concord-consortium/codap,concord-consortium/codap,concord-consortium/codap,concord-consortium/codap,concord-consortium/codap